A medical imaging technology is known which registers an ultrasonic image obtained in real time with other pre-obtained medical image such as a Magnetic Resonance (MR) image or a Computed Tomography (CT) image to obtain the mapping relationship between the position of an ultrasonic probe and a target position in the pre-obtained medical image and presents the other medical image as a reference image according to the position of the ultrasonic probe while imaging an imaged object through an ultrasonic imaging device using the mapping relationship.
In the foregoing technology, the mapping relationship can be obtained in the following way: after a certain reference part of the imaged object is imaged by the ultrasonic probe, the ultrasonic image of the reference part is registered with the image of a corresponding position, for example, a manually selected position, in the CT or MR image of the imaged object.
However, the mapping relationship between the position of an ultrasonic probe and a target position in a pre-obtained medical image is effective only when the position of an imaged object is kept unchanged. The foregoing process involving image selection and registration process needs to be repeated to update the mapping relation once the position of the imaged object is changed, for example, when the body of an imaged patient is moved. The operation of re-determining the mapping relationship is relatively tedious and time-consuming. Especially in the application scenario of an interventional surgery which needs a relatively long operation process during which the imaged object may be moved repeatedly, the processing load is increased and more time is consumed.